1. Technical Field
The present invention relates to adaptive cruise control sensing systems for automotive vehicles, and more particularly, to a method and apparatus for adjusting vehicle speed and inhibiting vehicle headway distance to a detected vehicle in response to shared vehicle network data such as the braking potential of proximate vehicles.
2. Background of the Invention
Adaptive Cruise Control (ACC) has reached a level of technical and business readiness such that it is beginning to appear in the consumer market as a comfort and convenience system. Consumer technical enthusiasm for ACC has increased because of their interest in intelligent vehicles and systems such as collision warning and collision avoidance. ACC performs as an enhancement to traditional cruise control by automatically adjusting a set speed, which is set by the vehicle operator, to allow a vehicle to adapt to moving traffic.
Under normal driving conditions the ACC system is engaged with a set speed equal to a maximum autonomous speed that is desired by the operator and the ACC system operates in a conventional cruise control mode. When the vehicle approaches traffic, the ACC system automatically adjusts the set speed to follow the traffic at a desired headway distance. This is usually a fixed parameter such as a one-second lead time. When the traffic clears or the vehicle changes lanes, the ACC system slowly resumes the speed of the vehicle to the set speed. When the vehicle approaches slow traffic, the ACC system is automatically disengaged and the operator manually follows slower vehicles in the slow traffic. When the slow traffic is no longer in front of the vehicle, the operator pushes the resume button and the ACC system accelerates the vehicle back to the set speed.
Auto manufacturers are also investigating radar, lidar, and vision-based pre-crash sensing systems to improve occupant safety. Current vehicles typically employ accelerometers that measure forces acting on the vehicle body. In response to accelerometers, airbags or other safety devices are employed. Also, Global Position Systems (GPS) systems are used in vehicles as part of navigation systems.
In certain crash situations, it would be desirable to provide information to the vehicle operator before forces actually act upon the vehicle. As mentioned above, known systems employ combinations of radar, lidar and vision systems to detect the presence of an object in front of the vehicle a predetermined time before an actual crash occurs. Other systems broadcast their positions to other vehicles via an inter-vehicle wireless network, and the positions are displayed to the vehicle operator.
It would be desirable to provide an adaptive cruise control system that takes into consideration the position of other vehicles as provided by the inter-vehicle wireless network and, should the situation warrant, optimize the adaptive cruise control functioning with respect to the shared vehicle data.